Yoga may improve asthma symptoms, Cochrane review finds

A Cochrane review has concluded that yoga “probably” improves quality of life and symptoms in people who have asthma. However, its effects on lung function and the use of medicines remain uncertain.

The Cochrane researchers found 15 randomised controlled trials that looked at yoga and asthma, including 1048 men and women in total.1 Most of the trials were conducted in India, Europe, or the United States. Most of the participants had mild to moderate asthma lasting from six months to more than 23 years. Five studies included yoga breathing alone, while the other studies had assessed interventions including breathing, posture, and meditation. Most participants continued to take their usual asthma medicine while taking part in the studies, which were conducted over periods of two weeks to four years.

The researchers found moderate quality evidence from five studies (375 participants) that yoga improved quality of life. On the Asthma Quality of Life Questionnaire the score per item improved by an average of 0.57 on a seven point scale (95% confidence interval 0.37 to 0.77). However, the researchers warned that the two trials comparing yoga with placebo or a sham intervention had found no difference in quality of life.

Evidence from three studies (243 participants) found that symptoms improved by 0.37 standard deviation units of the severity scores used (0.09 to 0.65). A small amount of evidence also indicated that yoga can reduce medication use. The effects of yoga on forced expiratory volume in one second were not statistically significant.

Two studies indicated improved asthma control, but very significant heterogeneity prompted the researchers not to include the data. No serious adverse events were associated with yoga, but the data on this outcome were limited.

The researchers warned that better quality studies with more participants were needed to draw a firm conclusion about yoga’s effects on asthma.

Zuyao Yang, lead author, of the Jockey Club School of Public Health and Primary Care at the Chinese University of Hong Kong, said, “Our findings suggest that yoga exercise may lead to small improvements in asthma quality of life and symptoms. However, it is unclear whether yoga has a consistent impact on lung function, and we don’t yet know if yoga can reduce people’s medication usage, or if there are any side effects of yoga for people with asthma.”